Dispersion Characteristics of a Grating-waveguide for Terahertz Radiation

The linear dispersion equation of a grating-waveguide driven by a two-mixed electron beam for an application in Terahertz (THz) radiation is derived with the help of fluid theory, and the interaction of beam-wave is analyzed by the numerical solutions. We study the growth rate of fundamental mode and the second operation mode, and find that the growth rate is considerably enhanced due to the presence of two-stream instability. The peak growth rate versus voltage ratio is investigated, and the result shows that it can be enhanced by the proper choice of voltage ratio.